Why does the jQuery resize event fire twice?

This is not a problem of jQuery. It depends on the browser implementation. The browser decides when to trigger 'resize'. And you can use window.onresize = function() {...} to test. It will be same. Nothing to do with jQuery. I tested on Win7 chrome, it is fired twice, and in Win7 opera/safari it's fired once.

JQuery: How to call RESIZE event only once it's FINISHED resizing?

Shows at least others are having this issue. In 1.3.2 it was listed as a bug because of something with the events system: http://benalman.com/code/projects/jquery-resize/docs/files/jquery-ba-resize-js.html